beforeinput

HTML

<div class="editor" contenteditable>
</div>
<div class="text_see">
</div>

CSS

.editor {
  background: #fff;
  border: 1px solid #afafaf;
  height: 200px;
  padding: 4px;
}

JavaScript

let editor = document.querySelector('.editor');
let textsee = document.querySelector('.text_see');

[
  'beforeinput'
].forEach(eventName => {
  editor.addEventListener(eventName, e => {
    let dataTransferText = e.dataTransfer && e.dataTransfer.getData('text/plain');
    
    textsee.innerHTML = e.data;
    
    console.log({
    	type: eventName,
      code: e.code,
      inputType: e.inputType,
      data: e.data,
      dataTransferText,
      targetRanges: e.getTargetRanges && e.getTargetRanges()
    });
  });
});